Embodiments of the invention relates generally to the field of footwear and, more particularly, to an article of footwear having a sole structure with openings formed therethrough.
Conventional articles of athletic footwear include two primary elements, an upper and a sole structure. The upper provides a covering for the foot that securely receives and positions the foot with respect to the sole structure. In addition, the upper may have a configuration that protects the foot and provides ventilation, thereby cooling the foot and removing perspiration. The sole structure is secured to a lower surface of the upper and is generally positioned between the foot and the ground. In addition to attenuating ground reaction forces and absorbing energy (i.e., imparting cushioning), the sole structure may provide traction and control potentially harmful foot motion, such as over pronation. Accordingly, the upper and the sole structure operate cooperatively to provide a comfortable structure that is suited for a wide variety of ambulatory activities, such as walking and running
The sole structure generally incorporates multiple layers that are conventionally referred to as an insole, a midsole, and an outsole. The insole is a thin, cushioning member located within the upper and adjacent the plantar (lower/bottom) surface of the foot to enhance footwear comfort. The midsole, which is traditionally attached to the upper along the entire length of the upper, forms the middle layer of the sole structure and serves a variety of purposes that include controlling foot motions and providing cushioning. The outsole forms the ground-contacting element of footwear and is usually fashioned from a durable, wear-resistant material that includes texturing to improve traction.
In conventional articles of footwear, the sole structure is formed so as to completely separate a foot of the wearer from the ground. That is, the insole, midsole, and outsole are formed as continuous, or nearly continuous, layers that provide coverage to an entire bottom surface of the foot of the wearer. The foot of the wearer is thus prevented from making direct contact with the ground, as the midsole and outsole separate the foot from the ground in order to provide cushioning, support, and traction to a wearer.
In some instances, however, a wearer may desire to enjoy a more natural, barefoot-like walking experience. For example, hikers may wish to feel the ground beneath them as they walk in order to experience the feel of walking over different terrains or materials, such as leaves, grass, and mud, for example. As another example, golfers may wish to have a greater feel of the ground beneath them in order to achieve greater stability during a golf swing. Conventional items of footwear deprive a wearer from achieving such an experience by completely separating the foot of a wearer from the ground.
Additionally, in some instances, a wearer may also desire to minimize his impact on types of natural terrain. That is, it is recognized that a hiker wearing conventional hard-soled footwear has a more dramatic impact on vegetation and soil than a barefoot hiker. Thus, a hiker may desire to walk barefoot in order to preserve a grassy trail and minimize his or her impact on that trail.
While hiking over certain terrain in a barefoot manner can produce a more enjoyable sensory experience, it is recognized that certain types of surfaces can be difficult to walk over while barefoot. That is, rocky terrain or hard surfaces, such as cement, may be hard on bare feet. Similarly, ground that is extremely hot or cold may cause a hiker to experience discomfort if walking over that surface barefoot. Thus, it is recognized that some form of protection is desirable for a wearer when walking over such terrain.
It would therefore be desirable to have an article of footwear that provides a wearer with the sensory benefits of barefoot walking It would also be desirable for the article of footwear to provide a wearer with some amount of protection from various types of terrain.